In a corresponding move, forward Jason Thompson will be released.
Varejao, 33, cleared waivers on Sunday after being acquired in a trade with Cleveland and subsequently released by the Trail Blazers.
The veteran center, who had spent his entire 12-year NBA career with the Cavs, reportedly had interest from the Thunder, Spurs and Mavericks in addition to the Warriors.
With Festus Ezeli potentially out until the playoffs after knee surgery, the Warriors were seeking depth in the paint.
– Kenny Ducey